Methods for producing cyclic compounds comprising N-substituted amino acid residues

Abstract

The present invention provides methods for producing peptide compounds. The inventors have found that a cyclic peptide compound can be produced efficiently by linking the N-terminal amino acid residue and the C-terminal amino acid residue of a peptide compound in a solvent containing one or more selected from the group consisting of water-immiscible solvents, water-soluble alkyl nitriles, and water-soluble ethers.

The invention claimed is: 
     
       1. A method for producing a peptide compound by a liquid phase method, comprising:
 step 1: linking an N-protected amino acid or N-protected peptide to a C-protected amino acid or C-protected peptide; 
 step 2: removing the N-protecting group after step 1; and 
 optionally repeating steps 1 and 2 a plurality of times to produce the peptide compound; 
 wherein the method does not comprise isolating the product of each of steps 1 and 2; 
 wherein each of the steps comprised in the method for producing the peptide compound is carried out in Solvent B, which is one or more solvents selected independently from the group consisting of toluene, 2-methyltetrahydrofuran (2-MeTHF), methyl tert-butyl ether (MTBE), dimethyl carbonate, anisole, isopropyl acetate, heptane, ethyl acetate, and 4-methyltetrahydropyran;
 wherein workup in each of the steps comprised in the method for producing the peptide compound comprises one or more operations selected from the group consisting of a liquid separation operation, a filtration operation, and a concentration operation; 
 wherein Solvent C is added for the liquid separation operation; 
 wherein Solvent C is a water-immiscible solvent which comprises one or more solvents selected from the group consisting of 2-MeTHF, dimethyl carbonate, anisole, isopropyl acetate, ethyl acetate, MTBE, cyclopentyl methyl ether (CPME), 4-methyltetrahydropyran, and heptane; 
 wherein the workup in the steps comprised in the method for producing the peptide compound comprises one or more of the liquid separation operation; and 
 wherein the peptide compound comprises at least one N-alkyl amino acid residue. 
 
 
     
     
       2. The method of  claim 1 , wherein the method for producing a peptide compound further comprises step 3 of removing the C-protecting group. 
     
     
       3. The method of  claim 1 , wherein the liquid separation operation comprises a washing operation of the organic phase. 
     
     
       4. The method of  claim 1 , wherein step 1 comprises condensing the N-terminal amino group of a C-protected amino acid or C-protected peptide with the C-terminal carboxyl group of an N-protected amino acid or N-protected peptide. 
     
     
       5. The method of  claim 4 , wherein step 1 is carried out in the presence of a condensing reagent. 
     
     
       6. The method of  claim 5 , wherein the condensing reagent comprises a condensing agent selected from the group consisting of T3P, EDCI, HATU, COMU, BEP, PyBOP, DMT-MM, and PyOxim. 
     
     
       7. The method of  claim 1 , wherein the N-protecting group is selected from Cbz, p-nitrobenzyloxycarbonyl, 2-naphthylmethyloxycarbonyl, diphenylmethyloxycarbonyl, 9-anthrylmethyloxycarbonyl, Teoc, Boc, trifluoroacetyl, Fmoc, or Alloc. 
     
     
       8. The method of  claim 1 , wherein the C-protecting group is selected from t-Bu, trityl, cumyl, methyl, or ethyl. 
     
     
       9. The method of  claim 1 , wherein either or both of the C-protected peptide and the N-protected peptide comprise 2 to 20 amino acid residues, and wherein either or both of the C-protected peptide and the N-protected peptide comprise at least one unnatural-N-alkyl amino acid residue. 
     
     
       10. The method of  claim 1 , wherein either or both of the C-protected peptide and the N-protected peptide used in step 1 in the final round of the repetition consist of 5 or 6 amino acid residues and comprise 4 or 5 N-alkyl amino acid residues. 
     
     
       11. The method of  claim 10 , wherein the C-protected peptide used in step 1 in the final round of the repetition is C-protected MeLeu-Ile-MeAla-Aze(2)-EtPhe(4-Me)-MeGly, and the N-protected peptide used in step 1 in the final round of the repetition is N-protected Hph(4-CF3-35F2)-Pro-cLeu-MeGly(cPent)-MeAsp-NMe2. 
     
     
       12. The method of  claim 1 , wherein the C-protected amino acid or a salt thereof or the C-protected peptide or a salt thereof is: 
       
         
           
           
               
               
           
         
       
     
     
       13. The method of  claim 1 , wherein the N-protected amino acid or a salt thereof or the N-protected peptide or a salt thereof is: 
       
         
           
           
               
               
           
         
       
     
     
       14. The method of  claim 1 , wherein the peptide compound is: 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
       
     
     
       15. The method of  claim 1 , further comprising linking the N-terminal amino acid residue and the C-terminal amino acid residue of the peptide compound. 
     
     
       16. The method of  claim 1 , wherein Solvent B comprises one or more solvents selected from the group consisting of 2-MeTHF, MTBE, isopropyl acetate, and ethyl acetate. 
     
     
       17. The method of  claim 1 , wherein Solvent B comprises 2-MeTHF. 
     
     
       18. The method of  claim 1 , wherein Solvent C comprises 2-MeTHF. 
     
     
       19. The method of  claim 1 , wherein the peptide compound comprises 8 to 20 amino acid residues. 
     
     
       20. The method of  claim 17 , wherein step 1 is repeated a plurality of times, and Solvent B in step 1 contains 2-MeTHF in an amount of 50% or more by weight at least 50% of the total rounds of step 1. 
     
     
       21. The method of  claim 17 , wherein step 1 is repeated a plurality of times, and Solvent B in step 1 contains 2-MeTHF in an amount of 50% or more by weight at least 80% of the total rounds of step 1. 
     
     
       22. The method of  claim 17 , wherein step 1 is repeated a plurality of times, and Solvent B in step 1 contains 2-MeTHF in an amount of 80% or more by weight at least once. 
     
     
       23. The method of  claim 17 , wherein step 1 is repeated a plurality of times, and Solvent B in step 1 contains 2-MeTHF in an amount of 80% or more by weight at least twice. 
     
     
       24. The method of  claim 1 , wherein the linking step 1 is carried out in the presence of a condensing reagent selected from the group consisting of T3P, HATU, COMU, BEP, PyBOP, DMT-MM, and PyOxim. 
     
     
       25. The method of  claim 1 , wherein Solvent B is 2-MeTHF. 
     
     
       26. The method of  claim 1 , wherein Solvent C is 2-MeTHF. 
     
     
       27. A method for producing a peptide compound by a liquid phase method, comprising:
 step 1: linking an N-protected amino acid or N-protected peptide to a C-protected amino acid or C-protected peptide in the presence of a condensing reagent selected from the group consisting of T3P, HATU, COMU, BEP, PyBOP, DMT-MM, and PyOxim; 
 step 2: removing the N-protecting group after step 1; and 
 optionally repeating steps 1 and 2 a plurality of times to produce the peptide compound; 
 wherein the method does not comprise isolating the product of each of steps 1 and 2; 
 wherein each of the steps comprised in the method for producing the peptide compound is carried out in one or more solvents selected independently from the group consisting of toluene, 2-methyltetrahydrofuran (2-MeTHF), methyl tert-butyl ether (MTBE), dimethyl carbonate, anisole, isopropyl acetate, heptane, and 4-methyltetrahydropyran;
 wherein workup in each of the steps comprised in the method for producing the peptide compound comprises one or more operations selected from the group consisting of a liquid separation operation, a filtration operation, and a concentration operation; 
 wherein a water-immiscible solvent is added for the liquid separation operation; 
 wherein the water-immiscible solvent comprises one or more solvents selected from the group consisting of 2-MeTHF, dimethyl carbonate, anisole, isopropyl acetate, MTBE, cyclopentyl methyl ether (CPME), 4-methyltetrahydropyran, and heptane; 
 wherein the workup in the steps comprised in the method for producing the peptide compound comprises one or more of the liquid separation operation; and 
 wherein the peptide compound comprises at least one N-alkyl amino acid residue. 
 
 
     
     
       28. A method for producing a peptide compound by a liquid phase method, comprising:
 step 1: linking an N-protected amino acid or N-protected peptide to a C-protected amino acid or C-protected peptide in the presence of a condensing reagent selected from the group consisting of T3P, HATU, COMU, BEP, PyBOP, DMT-MM, and PyOxim; 
 step 2: removing the N-protecting group after step 1; and 
 optionally repeating steps 1 and 2 a plurality of times to produce the peptide compound; 
 wherein the method does not comprise isolating the product of each of steps 1 and 2; 
 wherein each of the steps comprised in the method for producing a peptide compound is carried out in one or more solvents, wherein the one or more solvents comprise 2-methyltetrahydrofuran (2-MeTHF);
 wherein workup in each of the steps comprised in the method for producing the peptide compound comprises one or more operations selected from the group consisting of a liquid separation operation, a filtration operation, and a concentration operation; 
 wherein a water-immiscible solvent is added for the liquid separation operation; 
 wherein the water-immiscible solvent comprises 2-MeTHF, 
 wherein the workup in the steps comprised in the method for producing the peptide compound comprises one or more of the liquid separation operation; and 
 
 wherein the peptide compound comprises at least one N-alkyl amino acid residue.